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Do fighters have black boxes?
Or is it just commercial aircraft? I was watching an episode of Scorpion where an "F-120 Firehawk" crashed and they looked at its black box. So, do normal, non-imaginary fighters have them?

some do some don't, depends on the fighter, older models don't have them but newer ones will

Yes, most military aircraft, including fighter aircraft, are equipped with a "black box" called flight data recorder (FDR) / crash survivable memory unit (CSMU) / integrated monitoring and recording system (IMRS) / deployable flight incident recorder set (DFIRS).
Sources 1, ( B-1B, F-22, T-45, B-2, F-4, F-15, F-16, C-5 Galaxy, NATO AWACS, and the Space Shuttle)
2. (F-18, floating black box)

Do you know if it's encrypted? It seems like it would be a potential source of intelligence for hostile forces in a combat accident?

I think it's safe to assume that scenario is included when the box was designed; I am not 100% sure, but I expect the data to be encrypted.

They're often referred to as Crash Survivable Memory Units (CSMUs).  See http://www2.l-3com.com/edi/rtmu.htm

Any source to support your answer.

Recently watched a documentary about F18 fighter pilot training (Jetstream). There they show how an incident is investigated with recorded data, which also includes recording of the HUD.

@Firee Some sources added.

@DeltaLima -- for example, the NTSB analyzed the CSMU from the F-16 in the Moncks Corner midair

Do fighters have black boxes?

Almost all the 4th gen and 5th gen fighter jets have a flight recorder a.k.a Black Box.

I was watching an episode of where an "F-120 Firehawk" crashed and
  they looked at its black box.

In case of a crash both the Black Box and the Ejection Chip will have to be examined to ascertain the cause of the crash.
Data is stored in stacked semiconductor dynamic RAM memory boards.The manufacturers supply the software and hardware needed to read and analyze the data

Dynamic RAM would require a significant amount of power to retain its contents.  While I can see advantages to having a large quantity of DRAM within a black box, I would not think it practical as a medium for holding data for all the time between a crash and the recovery of the module.  More practical I would think would be to have the recorder contain both DRAM and flash, along with sufficient stored energy to copy the DRAM contents to flash when external power was removed.  Do you know if the recorders work that way?

Most flight recorders can record 256 distinct streams of digital data, or parameters, per second, and store them all for 25 hours before writing over them. The latest voice recorders can store 180 minutes of conversation, while the older ones store 30 minutes. Both kinds of data are stored in stacked semiconductor dynamic RAM memory boards.
The information recorded, the sampling rate, and the order in which the data are stored differ.

Dynamic RAM can be overwritten trillions of times without "wear", which is definitely a useful property, but will lose its contents unless it is continuously kept powered; powering a significant quantity of DRAM for a month would require a decent-sized battery.  I can imagine the cost of DRAM plus flash plus a battery sufficient to power them long enough to copy the DRAM contents to the flash as being cheaper than the cost of some other memory technologies, but I would think an unlimited-write zero-power memory would cost less than a battery sufficient to power DRAM for a month.

It's possible that flight data recorders include a DRAM plus a battery large enough to keep it powered, but I would find it surprising.  If DRAM or battery technologies have improved enough to make it practical, that would be interesting to know.

FRAM would be better I would think. 100 trillion write cycles, SRAM access speed, EEPROM non-volatility.  Example: http://www.cypress.com/file/209146/download ■ 4-Mbit ferroelectric random access memory (F-RAM) logically
organized as 512 K × 8
❐ High-endurance 100 trillion (1014) read/writes
❐ 151-year data retention
❐ NoDelay™ writes
❐ Advanced high-reliability ferroelectric process
■ Very fast serial peripheral interface (SPI)
❐ Up to 40-MHz frequency
❐ Direct hardware replacement for serial flash and EEPROM
❐ Supports SPI mode 0 (0, 0) and mode 3 (1, 1)


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Why do turbine engines take so long to spool up?
Piston engines reach full rpm within a second or two, but turbines take much longer. Why is that?

It's unclear from your question what you exactly mean. Do you mean the time to start up an engine, or to increase the RPM of an already running engine (e.g. from idle to full power)?

I'm not an engineer (which might be better suited to answer this) so this is from simplified things they feed pilots:
Jet engines take much longer to spool up (i.e. increase RPM) than piston engines, especially at low RPM because of the pressure ratio/increased airflow necessary to keep the compressor from stalling/surging/blowing up every time when changing power settings.
The (simplified) jet engine cycle contains a compressor that pushes air into a combustion chamber, where it burns, and then blows out the rear end rotating a turbine that moves the compressor from back where we started at.
If you "add more power" (i.e. put more fuel in) it takes a while for that extra fuel to produce more thrust, which in turn takes a while to accelerate the turbine, which will make the compressor spin faster, which will finally bring more compressed air into the combustion chamber to utilize all that extra fuel you poured in at step 1.
Adding power all of a sudden will increase the pressure in the combustion chamber, so much that air that is "upstream" (i.e still in the compressor) does not want to advance. The extra pressure in the combustion chamber did not have enough time to spool up the turbine, so now the compressor is underpowered to keep "pushing" compressed air into the combustion chamber. Air starts flowing backwards (i.e. from combustion chamber to compressor), engine surges, all hell breaks loose.
So there is a lag (electronically these days, the pilots can floor the trust levers as fast as they like) when the engines are at low RPM, the FADEC only adds a little bit of extra fuel, waits for the airflow to stabilize, then adds a little more, and so on.
I think the graph below might explain this. Every time you change RPM, you will increase Pressure Ratio (i.e. move up the graph), then you wait a little bit for Air Mass Flow to increase (i.e. move right). If you increase the Pressure Ratio too much, without the accompanying mass flow (which take a while because of inertia) you will enter the surge line.

A similar thing happens on spool down, albeit a gentler one.
Compare this with the piston engine where you put more air/gas mixture into the cylinder, it makes for a bigger bang, accelerates the piston faster, and the very next piston cycle you can theoretically get max power.

And turboprops take the middle ground. The turbine is always at 100% RPM and the prop changes pitch to keep it at 100%, in response to throttle input. Prop blade pitch changes very fast - less mass to move less distance; thrust comes on immediately.

@radarbob: It's not that simple, because turboprops have propeller attached to the low pressure turbine and compressor to the high pressure turbine. So the high pressure turbine still has to spool up. Fortunately while the turbines are independent, keeping the low pressure one at high rpm via prop pitch changes the pressures so that the high pressure one keep high rpm too. And high pressure turbines generally always run at higher rpm anyway.

It should be noted that output power of piston engine is also limited by RPM, because one cycle can only intake so much air and thus burn so much fuel. Just the margin between throttled down and throttle fully open is much bigger.

@JanHudec, I may have under-qualified my comment; prop pitch change, and so thrust, was practically immediate in the aircraft I flew. The turbine ran @ 100% and the prop governed to maintain 100% rpm. If parts of the engine were different that certainly was not evident in any procedures, limitations, or gages.

@radarbob: The turbine should mean the high pressure stage. I suppose the low resistance provided by the power turbine at high rpm but low power can keep the high pressure turbine running at 100% or almost so.

@JanHudec, The only turbine indicator was a turbine inlet temperature gauge - temp entering the turbine section immediately aft of the burner cans. Engine performance was all about the prop governing at 100% rpm. Every time I touched the throttles I thought prop, never turbine.

Car guy here.
Fundamentally, it's due to turbine engines relying upon the compressor charge to push the exhaust from the combustion chamber through the turbine blades. Increasing pressure in the combustion chamber too rapidly can push back against the flow from the compressor side, which stalls the engine and probably can damage the compressor blades.
On a piston engine, power is made in (mostly) distinct strokes. Rapidly increasing the pressure during the power stroke will not push back against the intake charge since the intake valves for that cylinder will be closed at that time.

And if the fuel/air charge is ignited too early in a piston cycle, it can destroy the engine!  (See "knock".)

Momentum is given by:
$$\mathrm{Momentum}=\mathrm{Mass}\times\mathrm{Velocity}$$
Work done is given by:
$$\mathrm{Work~done}=\mathrm{Force}\times\mathrm{Distance}$$
Work done is measured in watts, defined as joules per second.
Knowing this, you can see how a battery will behave with a bigger load.
A jet engine has a larger mass, and must reach a higher velocity. The work done to do so will increase too, with a more powerful battery doing more rotations. The thing is, it's not a proportionally larger battery. If you gave jet planes a really powerful battery, the work done would be huge, and a lot of force would be applied in very little time (high wattage), so that it would start up in the same time as a prop. However, this would be very energy inefficient (due to heating), so it works out best to use a smaller battery to start up over a longer period of time.

Dan, I interpreted the question differently.  Not how long it takes to start the engine from stopped, but how long it takes an idling engine to spool up.  I do know that first generation jet engines had prolonged spool up times, and modern designs spool up much more quickly, but I don't know the physics of why.

Ah, well the same thing can be applied.
The change in angular momentum between two speeds will be much, much greater on a jet engine, for the same reason as above :)

Dan, I just found this from the headline of an article in a "JET POWER" blog.  "Engine thrust is APPROXIMATELY proportional to the engine speed raised to the power of 3.5".  If this is correct, it means that an idling jet engine has very little surplus power should the thrust lever be advanced fully, until the engine spools up.  Coupled with your correct comments above about the rotating mass and angular momentum being larger than on a piston engine, it is clear that it will take longer for the jet to reach full power.

Not all jet and not all turbine engines have a larger mass than piston engines.

Even in the start-up, this isn't the only or even the main reason. In a piston engine, the engine itself will be helping to spin itself up within the first cycle. Once the first piston fires, the engine will accelerate up to idle speed very, very quickly. In fact, you really don't even need an electric starter at all. They're more of a convenience item and early piston engines didn't have them. You can start a piston engine simply by turning the power on and yanking the prop. Once the first piston fires, the engine will take the rest from there.

In a turbine engine, things are very different. It's not safe to begin combustion until the compressors are already running at a relatively high RPM, such that the combustion is contained within the combustion chamber. A jet engine doesn't have a sealed-off combustion chamber like a piston engine. The combustion is contained by the high air pressure produced by the compressors. If that air pressure isn't present yet (which it isn't in an engine that isn't spinning,) the combustion would not be contained and would fire right out of the front of the engine. Needless to say, that's bad.

Edit: In the part regarding the piston engine, I really should have said, "You can start a piston engine simply by turning the power and fuel on and yanking the prop." Obviously, it doesn't start if you don't give it fuel.

Oh, another issue regarding turbine engines: They don't typically use electric starters at all. They're started with external high-pressure air streams (either bleed air from an APU or an already-running engine or from a start cart.) See this question: How are turbine engines started?.

Though this question/answer is old: Work is measured in Joule (or NewtonMeters or WattSeconds). Power is measured in Watts. A human can pull a 100kg weight over 100m distance in several minutes, while a car can do it in a few seconds. The work is the same, but the power defines the time needed.

This answer makes no sense at all. It attempts to explain the behaviour of turbine engines without using any actual property of turbine engines, so it cannot possibly be correct. And what is the relation of a battery to force, work or turbine engines?

Jet engine have smaller mass than piston engine of same power.

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license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/

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Can Microsoft Flight Simulator help me learn to fly (or make me a better pilot)?
Microsoft Flight Simulator has "flight lessons" with a virtual flight instructor, some of which teach concepts that are taught during actual flight training. These simulators are becoming very realistic, and I can see them being helpful as an introduction to a subject prior to running the Hobbs meter and paying for actual flight time. Will this experience help or hurt someone who decides to become a real pilot? Is it a tool which can help students/instructors in an actual training environment?

From my experience as a Flight Instructor, IMO the flight simulator is great tool for practice of things like instruments, navigation, even working on communications where I pretend to be the Air Traffic Controller in less stressful environment. Like Abelenky's great answer though, they may never really feel like what it does to have real airflow over the controls [or bounce off the runway]. Long story short it's great for everything (especially emergency procedures) except the real stick and rudder stuff. For that there is nothing like the real thing.

I have always wondered what my chances of successfully stealing a plane and eventually landing safely in an emergency if all I ever had was MS flight sim.

Clarification:This was written about Microsoft Flight Simulator X (FSX).   Parts of the answer probably apply to the new Microsoft Flight Simulator (2020 release), but that isn't what I had in mind when writing this.  Maybe a new answer will be appropriate after using MSFS for some time.

@Pondlife gave a very good answer, and I'll add a few bits to that.
Even after having gotten my license, I still use flight sims (mainly Microsoft FSX and X-Plane 10) for some practice.
Before flying into an unfamiliar airport, or over an unfamiliar area, I'll often load it up in a simulator, and fly it.
Especially when I was a student, I found this incredibly helpful for my long cross country flights. You can look at a map all you want, but its still not the same as sitting in the simulator, and looking around ("I see the mountain on my left.... and the lake below me.  I can follow this valley all the way to the airport..." etc). And I've generally found the simulator, with good terrain and textures loaded, can be pretty close to reality.
The night before I did a student flight from KBFI to KVUO, I flew the entire thing in FSX. The next day, it really felt pretty much like making the same flight all over again. Based on the landmarks, timing, views, etc, I knew exactly where I was, and I was confident that everything was going right.

That said, in my opinion there are some things simulators do very poorly.
Some of these are:

TakeoffsThe application of power and left-turning tendency on the ground just doesn't feel realistic at all. The climb out doesn't feel right.

LandingsGround effect is difficult to observe in a simulator. The flare doesn't feel like reality, and touching down (or bouncing) is not realistic at all.

Cross Control, Slip, Spin & Unusual AttitudesAnything beyond basic maneuvers up to 30 degrees bank or 20 degrees climb doesn't match reality.

This is dependent on your simulator, some perform certain things more realistically than others.
Because of these limitations, I would NOT use a flight simulator to try to learn takeoffs, landings, or certain maneuvers. (You can learn the "procedure" in a simulator... when to reduce power, when to add flaps. But the "feel" will be all wrong).

If you're going to try to incorporate flight sim into your training, there are some basic things you should do:

Spend LOTS of time configuring itUnlike a video-game, this is not "plug-n-play". Spend time learning all the controls.
Turn on RealismWhen adjusting your controls, set all "null-zones" to zero, set "Sensitivity" to maximum, turn off helpers like "auto-mixture" and "auto-rudder", etc. (However, I do keep "Gyro-Drift" turned off in my sim.  Its annoying, and adds little practical value)
Turn on WeatherThe flight simulators typically come pre-setup with zero wind, good weather, standard temperature, etc. Configure yours to pull from real-world weather sources, or add some clouds, a variety of winds, and don't always fly at noon. Set the timing for early morning flights, twilight flights, night flights, etc.

Another "fun" area where flight simulators can be slightly helpful is in emergency procedures.
Typically in real-world training, my instructor told me:  "We're going to practice engine-out emergencies" and my mind immediately starts preparing for that... And naturally, we have to do them at a safe altitude in a safe area.
In a flight simulator, you can set up the computer to give you a random emergency at a random time. You might get the problem on short-final, or over a metro-downtown area. Something that you just can't do in reality.
I haven't had any real-life emergencies, so I don't know how accurate a flight simulator is. But I believe that some practice is better than no practice at all, and flight sim lets me fly into storms, icing, get lost in fog, fly approaches below minimums, have an engine seize up on me, etc, all without risking my butt or a $200,000 airframe.

Since @Lnafziger suggested more specifically addressing flight training:
I do believe that flight sim can help with certain aspects of training, but in other areas, it is no help at all, or actually harmful.
Training Areas simulators can help with:

ProceduresReviewing steps and procedures before going in the air.  For example, for a student, steep turns or stall recovery can be a little nerve wracking at first. It may be much easier (and cheaper) to do it in a sim with an instructor, discussing all the steps and reasons for actions. Then when the student gets in the air, they won't have the "feel" for it, but at least the general process is already familiar.

NavigationTuning and identifying VORs, and interpreting the needles can be done just as well be done on the ground as in the air. If the sim has good, realistic terrain (I prefer MegaSceneryEarth), it can also be used for some visual reference lessons.

Instrument interpretationScanning and cross-checking the 6-pack of instruments can be done in a simulator just fine, and a student can practice doing it for long periods of time for a fraction of the cost of flight time.

Training Areas simulators are very bad at:

On the ground & Outside the planeAnything on the ground, such as taxiing and parking, or anything outside the airplane, such as pre-flight inspection, or weather interpretation, just doesn't work in a sim.

RadiosI haven't seen any flight sims that really work for the practice of talking on or listening to the radios. (I haven't used VATSIM, which might help). I don't think there's any good substitute for actually flying in a real airspace while simultaneously engaging in real radio conversations.

FeelEven the best full-motion sim isn't a substitute for the forces a student feels in a real airplane. This is especially true on ground-reference maneuvers, takeoffs, and landings, where I feel sims fall far short of reality.  No one will ever get a "feel" for the plane from a simulator.

For much more information on the topic, I recommend these books:
Scenario-Based Training with X-Plane and Microsoft Flight Simulator

Microsoft Flight Simulator X For Pilots Real World Training

And here's a picture of my old simulator rig.
(Its been improved a bit since this picture)

Wow, that is a nice sim rig... obviously a lot of time and effort (and dare I say dollars) invested there.  Good job!

Thanks.   I estimate its around $800 in Saitek equiment (not all of it is visible in the picture), and probably another $200 in software add-ons (scenery, airplanes, add-ons).  I guess that's more than I realized until now. :)

You might consider editing you comments on radios considering that recent rise of PilotEdge, that's pretty darned good for practicing radios: http://www.pilotedge.net/

which is a better software to start with, MS FSX or X-Plane-10?

@MaxHodges I say XPlane if you have neither. FSX is OK, and because it's Microsoft it's on every shelf in every electronics store that sells PC games. XPlane, however, has a much more sophisticated physics/fluid dynamics engine and overall a lot more love went into coding it than any MSFS version I've seen or used. For $60 plus shipping to use on a home setup like abelenky's it's a great buy. Biggest downside is that only the major world airports are included, so if you want to hop around an entire metro area you'll need some scenery packs which are spotty.

@Jay Carr:  You suggested that I comment on radios over a year ago, and I declined.  I don't appreciate you editing my answer to put words in my mouth that I never wrote.  You are welcome to post your own answer, but such a significant revision to my answer is not welcome.

@abelenky Your answer is incorrect but because of historical momentum, there's little we can do to change the fact that it's marked as the correct answer.  I really wish you would update the answer in your own words.  I've asked on meta and chat about how to approach this and both times was told to edit your answer.  So I've done, though it is, of course, your prerogative to role it back.

I've very curious if any of the physics-related cons will go away with FS 2020. super excited for this game

@pushkin: Per the MFS-Alpha NDA agreement, I will not comment about MFS.  ;)

@abelenky you played with alpha?? lucky

It can definitely help: when I did my instrument rating my instructor used MS FS to walk through (fly through?) various procedures before doing them for real. He also used it for NDB training because the aircraft we used didn't have ADF. I found it very useful, and if I had bought it myself it would probably have saved me a lot of time and money. The main benefit for me was that it lets you run through procedures to practice getting all the steps right and in the right order; I've never used any scenarios like the ones you mentioned so I don't know how useful they are.
Another very useful simulator I've used is the Garmin G1000 PC trainer. The G1000 has so many features that trying to identify them all while sitting in an actual aircraft is difficult, even if you have the aircraft available and can pay for it. It also lets you practice various failure modes, which is often difficult to do in the real aircraft. Garmin provides simulators for their 'basic' aviation GPS units too, and they're great for the same reason: you can play around as much as you like. There's no doubt in my mind that they help very significantly.
I think that as glass cockpits become more and more common, simulation will become more and more important. They're great tools, but they also bring a lot of complexity and learning how to handle that complexity safely is a lot easier using a simulator. Of course you eventually need to go up, fly, and try out what you've learned for real, but it's no fun trying to flip through a G1000 user guide in flight.

I think that instrument training and practicing procedures is where simple simulators really shine!

I believe that there's an element to this question which has not been covered.  This is very much a personal response.
Your question specifically asks whether it can help you to learn how to fly or become a better pilot.  This is actually two questions in one.
Physical and mental limitations not withstanding, I would say that just about anyone can learn how to fly.  But I don't believe that everyone who can learn how to fly could be a good pilot.  Flying and pilotage are very much more than successfully operating a flying machine in order to fly.  It's even a lot more than doing that and following the procedures (ATC, operating in controlled airspace etc) which accompany it.
Being a good pilot requires a certain aptitude and attitude (and I'm not talking about what you see on the AH).  It needs, let's not beat about the bush, a reasonably good IQ and education.
A pilot becomes good when the operation of the machine or the following of the procedures is not enough to to produce a safe, successful conclusion.  A good pilot avoids the traps and pitfalls that catch the unwary and have proved the rule, all to often, that in the ongoing contest between the earth and flimsy machines arriving in other than controlled circumstances, the earth has yet to lose.
A good pilot takes care of the machine and it's passengers.  A good pilot can deal with the unexpected and make sound decisions to continue a flight or not or perhaps even to not commit aviation at all.  A good pilot has situational awareness which tells them, via sixth sense, that the bizjet calling left base is a potential threat and is already looking by the time the tower calls.
But much more than this, there are some very important elements to flying which a sim can never provide.
There is the emotional response; that thrill, that feeling of privilege, that unquantifiable human response to flying that is so much more than operating the machine.  There is also a set of skills and mental and physical responses without which, it is not possible to be a "good pilot" (IMHO).
Let me give a brief background of where I'm coming from and a concrete example of what I mean.
I have only a couple of hundred hours.  A handful on fixed wing, the rest on helicopters.  I also have about 3500 hours "flying" big tin on VATSIM (if you are serious about PC simming and don't know about VATSIM, Google for it right now!).
In VATSIM, I can operate a 777 (my favourite) very successfully including all of the related procedures which VATSIM does a remarkably good job of simulating.  I can fly a SID, follow my planned route, follow a STAR and do a visual onto 26R at Heathrow without breaking sweat, talking to and complying with ATC all the way. I can deal with an unexpected hold or a last minute change of arrival without fluster. I know this all works because I have also been lucky enough to do this in a "real" sim (737) and I had no problems at all using the automatics and hand flying the machine for the first 500 and last 1000 feet to depart and arrive safely back at Heathrow.
However, when I was learning to fly a helicopter, the reality of it all was very different.  Hovering is like learning to ride a bike.  I would say anyone with reasonable co-ordination can learn to do it.  I can hover all helicopters I've flown with ease.  Without even thinking about it.  Thing is, I can't really tell you how to do it and I have never been able to keep a PC sim helicopter in the air for more than a few minutes without getting into horrible shape.  Try explaining to a child how to ride a bike.  I reckon it's impossible.
When you switch from lurching around the sky with your instructor calling "I have control" every 20 seconds to that magical moment when you are suddenly in a steady hover, there are some things which simply cannot be simulated which your brain needs.
The beginners mistake is to focus on the ground, I think most people are looking about 15 metres ahead.  You cannot succeed like that.  What you want to do is focus your eyes well into the distance and let your peripheral vision do the work.  It's almost subconscious and I can't even tell you how it all works but you do realise that you are moving over the ground with subtle cues coming in from your periphery.
The second, and more important set of cues, are those that come through the "seat of your pants".  With a little experience, you just "know" when the helicopter moves, even before your peripheral vision has picked up the movement and you've already put that pressure on the cyclic (and it generally is pressure, not movement) to arrest the movement before the machine has deviated from it's position.  There are always small movements but to an external observer, you are sitting there, in the air, without so much as a ripple.
Subtle sounds are also important.  I can tell you pretty much where the rotor RPM is without looking at the tach and can certainly tell instantly when it's going down.  The second cue is from the tach but by that time, I'm already on the collective to adjust.  The tach just qualifies what I know and shows me that I'm doing the right thing to correct.
I'm sure that the fixed wing guys could provide good parallels.
My experience on sims tells me that you can indeed learn how to operate the machine and prosecute the procedures around it but it cannot help you to fly, nor to be a good (or better) pilot.  Where a sim can help is in teaching you the operation and procedures to the point where your brain is free to concentrate on flying and pilotage and your heart free to enjoy the sensations, because the mechanical stuff has moved into your subconscious and has become muscle memory.
Flying is emotional; it's passionate; it's determination; it's personal conquest; it runs in your veins. It's many things more than a sim can ever provide.
If you don't get "Oh I have slipped the surly bonds", then you are an operator, not a flyer.
[EDIT]
Am I a good pilot?  I'd say I'm average, and striving to be better, but that, in reality, probably describes most pilots, since it is impossible for most to be better than average.  I do recognise that I'm in that statistically dangerous zone where I have enough hours to think I'm good but not enough hours to prove it.  In my experience, ego and cahonas tell many pilots that they are good pilots ;)

Excellent answer about learning to fly!  You seem to have focused on one specific part of my question though.  I ask if it can "help" you learn to fly and "I can see them being helpful as an introduction to a subject prior to running the hobbs meter".  I did not mean to imply that someone can learn to fly solely with a simulator.  Thank you again for your insight!

I full agree with Simon here, VATSIM helped me a lot with understanding procedures, learning about radio operation and correct phraseology, airspace structure and everything that is of theoretical nature in aviation. So the only thing I had left to do when I started my PPL, was indeed learn how to fly the plane.

Superb answer!!

Crisp explanation. Aptitude and Altitude will take you to that Altitude.

I think IVAO deserves to be mentioned as well.

I spent a lot of time (years) flying MSFS before getting into a cockpit for real. Turns out I had developed a bad habit of using the instruments rather than my eyes. When simming I probably spent 80% of my time looking at instruments and the moving map and only 20% looking outside. The biggest surprise for me about IRL flying was that these ratios were reversed, at least in VFR.
Now being a pilot it is very helpful for practicing procedures, test-flying cross countries, and, with the ground detail in FSX, practicing navigating by reference to ground features (e.g. "IFR&R": I Follow Roads and Railroads).

Reading this I wonder if we are the same person. This exactly describes my introduction to flying. Took a bit of work to break the bad habits.

Happened to me as well. I realized in my first flight I spent the majority of time (or at least much more than I should have) starring at my G1000, essentially flying IFR, but in reality I should've looked outside for the beautiful view!

Sorry, I know that's not nice to read but all in all I like to answer your question with a no.
Flight simulators on your computer doesn't offer the possibility to learn how to actually fly an airplane, they even teach you to act in a different way and in my eyes this might be even very dangerous especially if you only have a little flying experience yet.
But there are exceptions: I now don't like to talk about flying but operating an airplane. A flight simulator for sure offers a good possibility to train procedures. To learn instrument approaches you maybe better go into a FNPT but other procedures and flows like organising approaches, work on a proper timing and workflow, practice briefings and even get used to some instruments. Tracking VORs and NDBs outbound from different positions, deciding for the right holding entry and all this stuff.
But once again, a PC flight simulator does not teach you flying the actual airplane and can even be a disadvantage for your initial flight training. If you get used to flying and handle your aircraft well, then it probably is a great way to learn more complex operations.
Another problem I've often observed is that people who 'trained' a lot on their computer become far too confident on what they are doing and very used to procedures which in the actual plane may not work. Always remember that you are a pilot who likes to learn and use the computer only as a helpful device to get a impression how things basically work. If then questions occur, ask your flight instructor.

This is kind of a yes hiding in a no -- I agree that a sim won't teach you the same skill and finesse you need to fly a real airplane (you couldn't do 40 hours in a sim and then go take a checkride in a Cessna), but as you pointed out they're useful tools for somethings like instrument procedures, emergencies, etc.

You say no, but then explain that sims can help develop skills and learn advanced operations; this seems contradictory to me, especially given that the original question is "can a simulator help me learn to fly (not teach me to fly) or make me a better pilot?"

And I will definitely stay with this no. It can not teach you to fly. I don't have an answer to the second part of this question. As I've mentioned, in my eyes it can even be counterproductive to work with a simulator during initial flight training. Later on it's really dependent on how you work with the sim and then, that's most important, adapt this in the aircraft. I can do a lot of things on the grount sitting in my sofa hut this doesn't make me a good pilot. A good pilot is who performers well in the actual plane and I have no experience allowing me to say that a sim. helped me uo there.

By the way, the part of the question you highlight is written in brackets in the actual question. The way he asked I assume @lnafziger to be a student pilot just beginning his training and the aim of ny answer is to provide him with what he needs to be awere of, when using a sim not to say that it isn't a nice toy.

@voretaq7, oh sorry I've not seen your comment yet. I like to disagree with you at the last point you mentioned. I would never train for emergencies in a pc simulator unless you have a detailed rebuild of your aircrafts flight deck. In this dase i would even prefer to sit on a simple chair maybe in front of a cockpit poster and actually point with my hands in the right directions a call out what I'm doing - that's also some kind of simulatin, not wgat you're talkin about, but in my eyes very useful.

@Falk I'll agree that if the panel you're training with in the sim isn't a good match to what you're working with in the real airplane you won't be able to work on flows (which is a huge part of emergency training - I learned flows with a poster the same way you describe :). My larger point is simulators are a tool (like foggles or those little suction-cup instrument covers): Used correctly they can be extremely valuable ; Used wrongly they may be dangerous.

@Falk: I appreciate the points you make, although for me the ability to practice things while only risking my ego is helpful. Once with an instructor I made a terrible landing in a stiff crosswind. Then at home I recreated it, repeating it until I found and learned from my mistake, which was I failed to hold the crosswind correction after touchdown.

@MikeDunlavey I appreciate that the use of the sim helped you to find out what the problem was. As you are know obviously in you initial flight training please consider one more fact: the computer doesn't offer you a propper image of the horizon and you will definitely tend to fly heads down. Try to avoid it flying with your eyes on the instruments,  that's even not flying some kind of "IFR". You'll have a lot of fun doing steep turns, approaches out of any situation, getting to the runway on the craziest way but all this is based on the look outside and a short glance on the A/SI.

I'm not a pilot so I can't answer the second part of the question, but a flight sim can definitely help with learning.
My story:
I've been "playing with" MS Flight Simulator ever since the first version came out for the original Mac's nine-inch black-and-white monitor. (It only had the Cessna 172, a Learjet, and a Sopwith Camel.) Many years later, while working at Microsoft, I was practically the only person in the office (not USA) able to do the product press demo at the launch of MS Flight Sim 97 (edit: it was more likely FS2000, a major upgrade in 1999). The Cessna is still in there. After the press conference (at an airport!), people were invited to try it for real; we had hired a couple of flight instructors and their ... Cessna's!
I was lucky to get the final slot, and I swear that the only thing the flight instructor ever touched was the radio, and the prop angle at take-off! I had never touched a real airplane before (except as an airline passenger, duh) but with my MSFS practice -- even without yoke and pedals -- I just felt right at home and every detail of the 10-minute flight was just as I expected it to be. My own impression is that my flight and landing was considerably smoother than the other "student" that I flew with.

Kind of an extraordinary claim, any evidence to back it up?  I want to believe you but...well, extraordinary claims require extraordinary evidence.  (Example: The last guy who made this claim (that I saw) had a video of the whole flight...)

@JayCarr you're right to be skeptical but I can only offer you my word for it. I could probably ask a few of my then-colleagues to confirm it but you'd still have a point - I have no hard data to point to. I've just spent a while looking for press articles from the time, but let's face it - that was before the Internet really took off (pun!) and I don't have any clippings from print media. (Dang it, why don't I?)

In my experience memories are sometimes magnified over time.  The further in time I travel from any event, the more modified the memory becomes.  My first flight was a long time ago.   All I have to record the event is a terse entry by my instructor in my logbook. Although I am not sure my instructor would back me up, it recall that it was an absolutely perfect flight.  Regardless of the actual or perceived events surrounding your first flight, I believe your answer conveys a love for flying.  I hope you are privileged to fly for many more years.

Can Microsoft Flight Simulator help me learn to fly (or make me a better pilot)?
You tell me??
First a story on flight simulation...
The number one defense contractor in the world. Lockheed Martin purchased the code for Microsoft Flight Simulator and turned it into Prepar3D.
Why would the makers of the F-22, F-16, F-35, C-130, C-5 do this if there was not something to it?
In today's world of drones, and children growing up with tech, Lockheed figured out an ingenious plan to save the military tons of money and make a profit.
By shifting training to a virtual environment including virtual reality software, flight simulators and even full on level D simulators the military will save money. Why spend \$14,000 per flight hour for a C-130 when you can simulate it. The full level D is \$800 per hour. And \$68,362 for a F-22... versus \$800.
Everything is going virtual in the military....
Even deicing...
De-icing simulator

Basically you start at what is the equivalent of flight simulator, and work your way up to MFTA's and finally to a level D class sim..... then you move on to the real plane.
The key is instruction.... Being a trained pilot, yes you can go back to flight sim and practice..
To conclude.....I am an FAA licensed Private pilot. I also have flown on VATSIM with flight simulator for over 10 years and flown everything from a C-172,  to a C-17 to a Boeing 777....
So could I really fly those?? Cessna... yes...but something bigger?? Yes after a very basic briefing by an instructor( takeoff speeds, landing speeds etc...) I solo'd a C-130 on my first flight. Well the Level D one.... at least.

Hello ARFLYER, welcome to Aviation.SE! Check out the Help Center for a quick introduction on how to answer questions, especially attribution of image sources and citation when producing statistical data.

And then there's UAV/drone flying, which I suspect is a lot closer to simulator flying than manned flight, as you have to rely more on the instruments and less on the feel.

Since I was a young kid I was addicted to flight sims. In all honesty, I think that is what really developed my passion for flying - I'm now 18 with a PPL.
What I found with MS:FS is that it really helped me in terms of understanding things. For example, how control input = output, how VOR works, and good airmanship. This led me to be 8 lessons ahead of where I should be, when I was 8 lessons in. - What would happen is that I'd go up with my instructor, and the planned lesson would be completed [well] within a few minutes, so they started the next lesson in the air.. 8 times in a row. I give this credit to flight simulator.
After what I like to call the "practical part" of flying, IE learning how to make the aircraft do as you want, MS:FS stops having a real effect.
You cannot properly learn to navigate, talk to ATC, taxi, do checks etc with a flight simulator. And, if you do it properly, you won't find any downsides with learning with one.
A common issue is that people may become obsessed with the instruments in a cockpit, and not look outside. Try and stay conscious of how much you use instruments, and I strongly suggest getting a peripheral such as TrackIR, which simulates head movement (best £100 I've ever spent). There are also online groups such as VATSIM which provide advanced tutoring to fly like a professional, with copilots and talking to voluntary certified ATCOs.
For a more realistic flight dynamics experience, I recommend Xplane 10, if your computer can handle it. I have some videos on my YouTube channel that show how sims can be useful for some things.
Happy flying :)

note that with flightgear and xplane you can use linux-track and any webcam for headtracking. ;)

I spend a bit of time using a flight sim (Lockheed-Martin's Prepar3D).  I have discussed this very question with CFI's and there is some disagreement.  A flight sim cannot "teach you to fly."  It can help you practice what you have learned in your flight lessons.  there are some caveats: 1) you have to have rudder pedals and a stick or yoke.  2) More monitors is better.  3) Using photorealistic scenery will get you more familiar with area.
A home rig with the minimum "bells and whistles" can run up to $1,000 or more.  That's about 5 hours of real world flight lessons plus ground school (If you shop around).  You can learn A LOT in 5 hours of flight training.

"You can learn A LOT in 5 hours of flight training." On the other hand, once you have that home rig set up, the marginal cost for additional simulator flight hours is zero. (You can of course add extras to the rig, and over time probably will, but that's unrelated in my mind.) The marginal cost of extra airframes is also zero, so you can try things that you don't dare try in a real aircraft, or which you fail at (compare Mike Dunlavey's comment on his crosswind landings). Even if the feel isn't perfect, even just knowing what caused you difficulties is a big step toward doing better.

I had Flight Simulator X for years, and I just got back into it.
I like it for a hobby and I like to plan flights, I don't expect to be a real pilot and I don't expect to jump into a plane and fly it I'm not that crazy, but I notice that began to know the instruments and what they are used for, I love FSX and I'm proud of being a FSX Pilot. I know one thing for sure is that I have great respect for the pilots who do fly real airplanes.
Another I like about FSX is that I can fly whatever aircraft I want to and don't have to pay or rent an airplane. I can't afford flight lessons so flying on the simulator is fun and can be very challenging especially when it comes to landing. For me I don't take it as a game but I take it as a learning tool, just in case I do decide to go to flight training, like I said earlier, I would not jump in a real airplane and try to fly it I would take flight lessons first, and hope that what I learn from the Flight Simulator would help me advance quicker.

Welcome to [aviation.se]! While some of the things that you've mentioned are true, it'd be good to provide an explanation of why and/or how Flight Simulator can be used as a learning tool, and whether or not this experience would be harmful should they decide to become a real pilot. Thanks!

" Will this experience help or hurt someone who decides to become a real pilot? Is it a tool which can help students/instructors in an actual training environment?" I think if this was edited slightly to answer the OP's question, it would be a great answer. ;)

Though in the presence of other great answers, my two cents are just worth two cents.
I read at several places that chair flying at home is very beneficial during flight training. However it appears to be very boring. A better alternative is always a flight simulator. As everyone has mentioned, it is not a replacement to actual flying, but at least it makes you prepare for the steps to do in a certain situation.

Chair flying, while boring, is pretty useful.  Even simulator flying is pretty boring.  The practice flight I described in my post was about a solid hour of just listening to my computer speakers BUZZZ while staring at the screen, and occasionally adjusting course 10 degrees.

While I agree with you, I don't know that this actually answers the question and would probably be better as a comment.  :-)

Yes it can. That is the purpose of a flight simulator. In fact, they are designed to help improve your judgement. Even though most simulators do not achieve this feel perfectly, your brain senses an upcoming object as the source, and therefore, your judgement comes into play.
However, flight simulators do not give you the full experience, such as fear. Many times people get scared on their first flight.
I suggest looking at guides or manuals of planes to completely operate them to their full potential. Think of flying a plane almost like driving a car. You need quick judgement to apply the brakes, and not get scared when a car drives too close. Though it is not completely comparable to a car, it takes a lot less time to stop it then to safely stop a airplane. Now I'm not an expert on flight, but I know enough.

Can you provide citation or what you base your assumption off with this statement: Though it is not completely comparable to a car, it takes a lot less time to stop it then to safely stop a airplane.? Most General Aviation light planes can stop fairly quickly and I would be surprised there is statistical data to prove this.

The original poster does not notice that he/she is actually asking two different questions: learn to fly, and learn to become a better pilot.
The value of a sim (any sim!) to learn to fly is VERY (extremely) limited. You get no feeling for the tactile movements and responses in the plane. For that reason the FAA also allows only 2.5 hours credit of sim time (even in an AATD, an Advanced Aviation Training Device) for the PPL, as per AC 61-136. So the value of a desktop sim is even less -- given that the value of even an AATD is so limited.
The value of using a sim (incl. a desktop sim) to learn to become a better pilot is much higher. And here too, the FAA recognizes this with higher credit in the AC 61-136, such as 20 hours for the IR and 25 hours for the CPL.

I believe so. Although it is not 100% as accurate as a real flight simulator, it does help you understand a basic concepts which can help you get a boost in starting your understanding in an aviation career

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text:
Why does a clean configuration lead to the generation of greater wingtip vortices?
"Slow, heavy, clean" are the three major conditions generating stronger wing vortices. It's very clear how "slow and heavy" aircraft create stronger vortices, but why a "clean" configuration generates stronger wake turbulence is less clear.
I did some digging on this, and found some people saying "use of the flaps reduces the AoA and thus leads to weaker wake turbulence" and others claiming "use of flaps moves the center of lift toward the root of the wing and that leads to less lift around the tip of the wings and thus less wingtip turbulence.
Which explanation is correct?
Edit) I checked the answer given here What is the relationship between angle of attack and wake turbulence?, but I'm not really sure "not really" is the right answer to this. The AIM (Aeronautical Informational Manual) is very clear about this, designating "clear" (along with "heavy," and "slow") as one of the three factors that increase wake turbulence.

Any valid explanation should also deal with conservation of momentum and energy. To generate the same amount of lift while accelerating the air less requires either accelerating more of it (that is affecting it to bigger height above and below the wing) or accelerating it more uniformly (that is changing the lift distribution closer to elliptical).

@lemoncider do you have a source for the 'slow, heavy, clean'-statement? As can be seen from the duplicate, another individual also found the same statement, so I believe some source is providing wrong information.

What if the AIM is wrong? It would not be the first time that a meme goes unchecked. Gear and flaps have a very minor effect on wake turbulence.

@ROIMaison Yes I have. Click on this link: https://www.faa.gov/air_traffic/publications/media/aim.pdf. In 7-3-3 (p.519), the manual says: "The greatest vortex
strength occurs when the generating aircraft is
HEAVY, CLEAN, and SLOW. "

I would actually assume the opposite to be true.
Let us assume the vortex intensity and the induced drag are directly correlated. The induced drag coefficient can be expressed as:
$c_{Di}=\frac{c_L^2}{\pi\cdot AR \cdot e}$

$c_L$: Lift coefficient
$AR$: Wing aspect ratio
$e$: The so-called Oswald factor, a number which equals one for elliptic lift distributions. It decreases for distributions that deviate from the elliptic one.

Most wing designs aim to achieve an elliptic-like lift distribution in order to minimise induced drag in clean configuration.
As flaps, spoilers, air-breaks and so on are deployed the lift distribution will deviate substantially from the elliptic one (see diagram), hence reducing the $e$ factor and increasing the induced drag. If the first assumption still holds, an increase in induced drag will have been caused by an increase in vortex intensity.

Additionally, significantly higher lift coefficients can be achieved with deployed high-lift devices, which also contribute to increase vortex intensity.

This might be true if the lift coefficients with and without flaps are compared at the same AoA, but the thing is the AoA needed for takeoff and landing changes when flaps are deloyed or retracted in actual flight. For example, we would need higher AoA for landing without use of any flpas, but with flaps the AoA needed for the same lift is lower than that. Personally, I think the key is here, but I'm not sure.

@lemonincider, note that the formula does not contain any $\alpha$ term, only $C_L$, so what is compared is the same $C_L$ That depends on $\alpha$, but we don't care about the actual values of that, only values of $C_L$.

@lemonincider, also the values of $\alpha$ are somewhat arbitrary here—the flaps increase the incidence of both the chord line (connects leading and trailing edge and the trailing edge moves down) and the zero-lift line (by even more, because camber increases).

@JanHudec Thank you for correcting me. So should I conclude the writers of the AIM are simply wrong? As far as I know this theory has been around for quite a long time and it's difficult to believe the AIM got this wrong.

@lemonincider, I am inclined to think that yes, it's wrong. After all it would not be the first widespread misconception about aerodynamics.

You need to multiply the lift coefficient with the local chord to arrive at the circulation. With a tapered wing the circulation distribution, which determines efficiency, will look already quite different from your lift coefficient plots.

Yes, I can't believe Circulation has not been mentioned yet. The theory of lift says the circulation around the wing is proportional to lift, and such circulation should be equal to exiting the wingtips. This answers says its prop. to lift squared...

What causes wing vortices? When the wing produces lift, there is higher air pressure underneath it, and lower air pressure on top of it. At the wing tip the high pressure air flips over to the low pressure air, and this creates the rotational element of the vortex, as described in this article. The more lift is generated at the wing tip, the stronger the vortex will be.
Aerodynamic lift is a product of lift coefficient, air density, air speed, and wing area. For subsonic speeds: L = $C_L$ * ½ * ϼ * $V^2$ * A. Only the factor ½ in this equation is a true constant! We have one equation with five variables, so lets have a look at what varies when.
Contrary to our first instinct, wing area is not a constant. Modern aircraft have Fowler flaps at the trailing edge, which are extended outwards and increase the wing area, as well as changing the curve of the wing which increases lift coefficient at a given AoA. So there is the first part of our answer: with deflected flaps we have more wing area to produce a given amount of lift, therefore lower required air pressures, therefore less air flippings at the wing tip :).
The second part of our answer also has to do with flaps. Elliptical lift distribution is only possible when the wing tip has zero AoA, a situation designed to occur in cruise. A clean wing configuration is designed for the cruise condition, where there is lots of airspeed to generate lift and we want to keep induced drag to a minimum. This same clean wing is very ill suited to produce the same amount of lift at the lowest possible landing speed.
CL is a function of angle of attack and of wing shape. The answer with the graph of CL shows CL at constant alpha as a function of flap deflection. A graph of CL at constant flap deflection as a function of alpha would show relatively more lift generated near the wing tip, and that is where the wing vortices are generated. Flaps are located more inboard, meaning that when deflected, a greater portion of the lifting force is generated away from the wing tip.

I've seen both of those reasons used to explain this, and probably they both contribute to it, but in my CPL training I was taught the reason is that a non-clean aircraft (and remember that this includes landing gear, spoilers, slats, etc.) causes airflow to be disturbed which reduces vortex generation.  The statement is always made referring to 'clean', not 'flaps retracted'.
The question came up also on Quora, and two answers came back, one with the reasoning I gave, and another using the increased AoA concept.

I am not sure that everything is so simple and obvious regarding flaps and gear.
Actually with flaps we have at least four points for vortices generation: on wing tips and on flaps outer edges, and they can mix with each other. FAA/EASA answer seems based upon the following NASA research, and takes into account combining wing tips vortices with flaps/gear vortices, and faster weakening of total vortex strength. I suppose that it really makes sense: aircraft in clean configuration generates "traditional" rather well-studied vortices, while aircraft in landing configuration generates much more complicated interfered turbulent flows. It is very hard to say which one is stronger and more dangerous.
Very interesting thread about the subject can be found on PPRuNe, with nice pictures of totally confused situations when vortex from the left wing is dissipating, while the right one remains stable and narrow.
And here is one more research about wake turbulence with interesting results.


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Is there a public NOTAM archive that's searchable by airport?
Pilotweb lists NOTAMs currently in effect. Is it possible to view or sort the history for a particular airport?

On Pilotweb, there's a "Federal NOTAM System (FNS)" section on the right side of the screen. If you select "NOTAM Search" it takes you to another NOTAM search tool. If you then select "Archive" from the drop-down list, you can search by date and location.

Thank you, I clicked the arrow and it turned green on my iPad. Hope that credits a correct answer.

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What is a simple way to explain why best range airspeed is below normal cruise airspeed?
Without using complex mathematics, please explain why best range airspeed is less than normal cruise airspeed.

Welcome to aviation.SE! This question might be helpful. You might also like to check out the [tour] if you're new to the site.

I thought it was a good question.  Can you provide an example of how you might rephrase this to be more specific?

Normal cruise is a compromise between being fuel efficient while getting to your destination at a reasonable speed.  It all comes down to drag; the faster you go the more parasitic drag you pick up and economy suffers.
Just like in your car - if you wanted to squeeze max efficiency (range) out of a trip you could drive at 55mph on the freeway.  In fact you could even make it law!  But, people are generally willing to burn a little more fuel to get there faster.

Also in commercial operation, the crew is paid by the hour and flying faster also means flying more miles each day and that means more revenue.

Yes, good point Jan!


text:
Did DB Cooper's aircraft land safely with the aft stairs open?
I've never seen a 727's aft stairs open, but presumably, based on an Wikipedia image and common sense, they do reach the ground when the aircraft is on the ground. Furthermore, (as I understand it), airliners land with a positive pitch, which means that assuming a level runway, the rear of the aircraft will touch down first. However, this suggests that if the aft stairs of the 727 were open during landing, they would impact the ground during landing and, given the pitch, do more than scrape the ground and cause damage to the aircraft.
However, DB Cooper's jump left the aft stairs open, and (as far as I can tell) it seems that the landing was uneventful besides the stress of having a hijacker potentially on board (although it's quite understandable if no one made any record of it, given there were slightly more important things to deal with).
If DB Cooper's flight did land without damage, why is that—did the 727's aft stairs not fully touch the ground? If the stairs did impact the ground, was there sufficient damage to require repairs?
(I meant this question to be more about the 727 than DB Cooper, but since his was the only landing with stairs open, there wasn't much room for speaking in general terms).

wikipedia say they were deployed

Its possible that they were not fully deployed, i.e., not completely down and locked.

The aft airstair was partially deployed for the duration of the approach and landing.
The transcripts of ATC communications between NW305 and various ground stations are freely available (and a fascinating read). The relevant communications (with Reno) begin on PDF page 87 (numbered 213). Below are the mentions of the airstairs from that point on, with times given in PST, 1971-11-24. I added the text in brackets for clarity.

22:35, NW305: OKAY AH WE'RE TRYING TO MAKE CONTACT WITH [Cooper in] THE BACK [of the airplane] NOW AND AH WE'RE GOING TO GET THESE
STEPS UP BEFORE WE CAN MAKE OUR LANDING...
22:43, RENO: NORTHWEST THREE ZERO FIVE WHAT'S THE STATUS ON THE STAIRS NOW SIR
22:43, NW305: AH WE HAVEN'T BEEN ABLE TO GET AHOLD OF ANYBODY [in the back of the plane] YET UH TRYING TO CONTACT HIM AND THEY'RE STILL
DOWN SO I WE HAVEN'T DECIDED YET AH WE MIGHT COME IN AND LAND WITH
THEM DOWN THERE'D BE SOME SPARKS SO
22:48, NW305: APPROACH AH THREE ZERO FIVE WE CAN'T SEEM TO RAISE HIM BACK THERE WE KIND OF HATE TO WE'D JUST AS SOON LAND WITH THE
THING HANGING DOWN IT ISN'T ALL THE WAY DOWN AND THEN PROBABLY WON'T
HAVE ANY PRESSURE ON IT SO WE HOPE IT'LL (unintelligible) FREE...
22:57, NW305: ...WE'RE NOW MARKER INBOUND AND UH AH WE'RE GOING TO BE LANDING WITH THE AIR STAIR IN THE DOWN POSITION AH WE DON'T SEEM TO
GET ANY RESPONSE FROM OUR FRIEND IN THE BACK
[The aircraft touches down and is taxiing.]
23:03, NW305: SEE ANY SPARKS COMING OFF THE TAIL AT ANY TIME ON AH TOUCHDOWN
23:03, RENO: NEGATIVE NONE AT ALL THE ONLY THING THAT'S VISIBLE ON THE TAIL IS LIGHT AH APPARENTLY ON YOUR RAMP
23:03, NW305: ROGER UNDERSTAND STAIR LAMPS AH STAIR LIGHTS
23:03, RENO: I DO SEE SOME AH SPARKS NOW JUST A FEW AH TRAILING YOU AH AS YOU'RE TAXIING IN
23:03, NW305: OUR AH PASSENGER TRIED TO DISEMBARK
23:03, RENO: I STILL DON'T AH GETTING A FEW SPARKS NOT VERY MANY AT ALL
23:03, NW305: OKAY WE'LL TRY TO SLOW OUR TAXIING HERE AS MUCH AH IT PROBABLY IS DRAGGIN AH

Why did the crew not retract the airstair before landing?
The airstair can only be operated from two positions: one in the main cabin and one on the exterior of the aircraft. It cannot be operated from the flight deck. The testimony of Tina Mucklow, the flight attendant whom Cooper interacted with almost exclusively, reveals that

Approximately four minutes after takeoff, [Cooper] stood up, told [Mucklow] to go to the cockpit and close the first-class curtains, and for no one to come out from behind the curtains.

It should be noted that the airstair was still closed and locked at this point. In fact, it was Cooper himself who performed the deployment:

...he asked her to demonstrate to him the procedure for opening the rear door and extending the stairway. She did this and was under the impression that he understood how to do it. She commented that it occured to her at this time that this was the only function of the aircraft which she had discussed with the hijacker during the time she had been with him which he did not seem to be fully aware of.

Even though before Mucklow left Cooper in the cabin "...she pleaded with him to take the bomb with him and he said he would take it with him or disarm it...", nobody could be sure, so complying with his demand for no one to enter the cabin was the obvious choice. Even after the crew suspected he had jumped, there was still some chance that he was present. That—on top of the clearly dangerous situation of being unrestrained in an airborne jet transport with a door open—compelled the crew to sit tight in the cockpit and land with whatever configuration they could control from there. Indeed, third officer and right-seater on the flight Bill Rataczak stated that

...no member of the crew departed from the cockpit to check on the presence of the hijacker following the arrival in the compartment of hostess Mucklow, who had locked the door behind her.

How did the airstair remain partially deployed on its own?
The airstair is in contact with the tarmac when deployed on the ground. In fact, it's designed to essentially wedge itself against the ground and act as a tail stanchion to keep the airplane from tipping backward during loading and unloading. Early 727s such as N467US had mechanical locks for the airstair in both the extended and retracted positions to accomplish this function.
However, the crew had evidence that the airstair was not locked, as Mucklow "observed the red indicator light go on the [flight engineer's] panel indicating that the stairs had been lowered." On the 727-100, that light would be de-energized only if the airstair was locked either up or down. (On the -200, a green light was added to indicate a fully extended and locked position.) The ATC transcript indicates the captain's later belief that the airstair wasn't "all the way down", so it's reasonable to assume the warning light remained illuminated.
That the airstair didn't lock down when deployed indicates that it never fully extended. It is likely that the air loads simply prevented full extension. The airstair hydraulic actuators were not designed with the strength necessary to overcome a 170-knot airstream, especially on early 727s. The extension was limited by the airspeed and subject to fluctuations with changes in the airstream and the weight of Cooper upon the stair.
The inability to fully extend the airstair in flight was even known on the ground beforehand, as the transcript of communications between NW305 and the airline's base at MSP reveal (I cleaned these up):

18:38, MSP: DON'T KNOW OF ANY WAY TO LOCK STAIRS IN AN INTERMEDIATE POSITION.
18:40, NW305: ...STAIRS WILL OPEN ABOUT 20 DEGREES AT 120 KNOTS. IS THAT ENOUGH FOR AN INDIVIDUAL TO ESCAPE THE AIRCRAFT?
18:40, MSP: WITH HIM ON STAIRS WILL OPEN POSSIBLY ENOUGH FOR HIM TO GET OUT. REMAIN UNPRESSURIZED. BE IN LANDING CONFIGURATION WITH
FLAPS. SLOW TO [APPROACH] SPEED BEFORE TRYING TO EXTEND STAIRS.

As it turns out, the stair could not be opened much if at all at 170 knots during a climb, and the captain had to "have 'er about down to a hundred and sixty knots" and level off at 7,000 feet to get the resistance low enough. It makes sense that a higher angle of attack would cause a greater air load on the door due to the increased frontal area. It also makes sense that the airflow alone would be insufficient at any speed to completely re-close the door due to the geometry of the empennage, the weight of the stair, and some hydraulic damping. Once the door was open, the crew were able to climb again to 10,000 feet and keep the airspeed "in the vicinity of one seventy, one eighty [knots]".
Although the hydraulic actuators would have provided damping, the swirling wakes from the landing gear and flaps—not to mention the aircraft turbulence inherent when flying low and slow over mountains in a storm—undoubtedly wrenched the stairs up and down considerably. Cooper's exit has been romanticized as a high-dive into the unknown, but it was more like trying to exit a springboard during an earthquake, with his own weight just exacerbating the problem. We know as much from Richard McCoy, Jr., a copycat hijacker who survived his jump (at the same airspeed) and was later captured and interviewed:

...[McCoy] stood geared up in the open doorway for a very long time before
descending the aft stairs. It was almost midnight, the sky was black,
and the wind was freezing, yet his hands were sweating. Finally, he
was able to collect his wits, take a deep breath and step outside onto
the stairs.
As he stepped out, the entire stairway dropped two feet under his
weight. Knocked off balance with his 70-pound duffle bag between his
legs, he grabbed the right handrail and wrapped both arms around it,
desperately holding on. The stairs shook and vibrated. The noise from
the jet engines on either side of him was horrendous.

In fact, it was cabin-pressure fluctuations caused by Cooper descending and exiting the airstair that allowed for the determination of exactly when he jumped (8:11pm PST):

Crew reported oscillation of cabin rate-of-climb indicator. This probably due to [Cooper's] weight now on stairs, stairs extended further, resultant effect on cabin pressure.

The FBI's analysis was that "When [Cooper] jumped, the air stairs were forced closed (by outside air pressure) causing an increase in air pressure similar to shutting a car door with the windows up". Although we've established that the door was not forced completely closed and locked, it's clear that the airstair was able to hang somewhat freely in the airstream, its deflection affected by air loads, the weight of Cooper, its own weight, and any dampening provided by the actuators.
What was the risk of landing with the airstair deployed?
The crew knew from the cockpit indication that the airstair was neither down and locked nor up and locked. But they had prepared somewhat for the idea of landing with a deployed airstair before they even departed Seattle:

19:27, MSP: IT WOULD PREVENT ANY SUBSEQUENT TAKEOFF IF YOU LAND WITH [THE AIRSTAIR] DOWN.

Mucklow advised Cooper more than once of this fact, given that Cooper had stated intentions to get to Mexico and that Reno was just a necessary refueling stop along the way due to Cooper's wanting to be flown low and slow.
Landing with a deployed airstair could have a range of consequences that had never been investigated or analyzed, so most likely the airline was playing it safe. At the very least, a detailed inspection would need to be carried out before the airplane flew again. If the stair were downlocked, the results of a landing would depend on what failed first. If only the latch failed, you might get away with just dragging the stair, which would cause some exterior damage but overall that'd be a relatively minor fix. If nothing on the airstair failed, I suppose you could bend the entire fuselage. I'd also worry about bits and pieces of failed components being rocketed around the empennage or into the cabin.
Fortunately, at this point the crew was safe from the worst outcomes because the stair was not downlocked. In fact, as we've seen, the crew knew that even at 120 knots the airstair would not be deployed far enough to strike the ground upon touchdown. That speed is in the ballpark for an empty 727 on landing, but even at a lower speed it's entirely plausible that the airstair did not strike the ground on touchdown, and was only able to fully extend once the aircraft was at taxi speed.
What damage did the aircraft sustain?
Given everything we've covered so far, the damage was probably not extensive. Dragging the stairs along at taxi speed would mean not much more than some sheet-metal repair. Looks like some of the railing paneling sheared away, probably in the air:

There's also the placard found in the forest a few years later that got ripped away at some point during the flight.
In any case, the crew was able to easily deplane via the deployed aft stairs:

23:14, NW305: ...WE'LL GO DOWN THE BACK STEPS AND AH AH WE'LL BE TAKING LEAVE OF THE AICRAFT AND SHUTTING IT DOWN AT THIS TIME...

"The transcript does not prove that the stair was down." Um, it kind of does.

AH? Is that some kind of marker or code, because it appears quite often?

@Peter Just a transcription of pilot talk.

Trying to locate the PDF containing the ATC transcript - the link to the Seattle PI blog post is now broken. Anyone? Thanks.

@ThomasHanser I've updated the link.

I do not think they landed with the airstairs down: The airstairs are powered to get them back up since they are heavy, and this feature can be operated from inside the aircraft as well.
The following answer is of Yahoo answers and while I can't confirm is accuracy, it sounds very plausible:

There are 2 control handles for the airstairs on a B727, one under a
  panel on the lower fuselage right beside the stair forward hinge
  point, and one at the top of the stairs behind a panel on the left
  side which can only be accessed when the rear cabin door is open.
  Because the cabin door can only be opened when the aircraft is
  unpressurized, this usually would prevent its actuation in flight.
  However, after the D B Cooper hijacking a device was added referred to
  as an anti-hijack vane that would swing over when the aircraft was in
  flight and prevent the door opening. To close the door either an
  electric hydraulic pump has to be turned on in the cockpit, or a hand
  pump beside the lower control operated while either handle is held to
  the close position. The door will free fall open without hydraulic
  pressure, but the support arms may have to be pushed to an overcenter
  position.

Assuming that the air stairs were deployed, it may be that the force of the airflow passing by would have been sufficient to spare the stairs from a tailstrike. The stairs have a large surface area and moving at perhaps around 100 knots when the nosewheel touches down would still generate a considerable force to push them into the fuselage.
The term deployed may also suggest that the airstairs may have been damaged and uable to retract the whole way, leaving it halfway stuck but still out of tailstrike range.
The aircraft was empty at the time which would have helped in either situation.

I am a B727 pilot to this day (5,000 hours on type) and I am pretty sure that if one tried to land a 727 with the airstair locked down, there would be a considerable amount of damage and the possibility of a serious accident. The two hydraulically operated struts that operate the airstair are downlocked "over center", They are operated by B system hydraulics which would have been working throughout the flight. Trying to retract the stairs while standing at the rear door with the airstair deployed in flight would be very daunting. You have to hold the handle towards you until the stairs are fully up, at which time the handle moves to an over center position and the stairs remain locked up. If the handle doesn't move to the over center position, the stairs will deploy again to the down position. The only way they won't lock down is if you remove B system hydraulics. In flight it is also possible that the force of the airflow on the airstair at 120 knots could be strong enough to prevent the airstair from reaching the down and locked position. Therefore I suggest that if they did not retract the airstair before landing (which apparently they didn't), and the B system was working normally, the only other possibility is that the force of the airflow on the door kept it floating halfway up.
As a matter of interest, the airstair was removed for the test crash of a 727 in the Mexican desert as this is probably the case.
You can see the over-center downlock in this video. I will make a video of the operation of the handle at the rear door in a few days if there is enough interest.

It would be desirable if the source of these two images (the aft stairs system and the flight engineer's lower panel) were identified.

They come out of the Boeing 727 Flight Manual.

The fact is simple geometry would prevent landing a 727 with the aft airstairs in the extended position. These stairs are have almost no clearance from the ground when they are extended. Check the relation ship of the tail strike bumper to the profile of the Aft airstair. You simply couldn't complete an approach at a flat enough angle for a successful landing. So maybe the aft airstair were damaged during the landing? Not possible. The 727 being a T-Tail with 3 rear engines is extremely tail heavy. So much so that the rear airstair doubles as tail support structure for the aircraft when parked or loading. Just the weight of the demountable engines are roughly 4700 lbs each, so we're talking 14,000 lbs independent of the T-Tail structure. When powering back a 727 from the gate the most important rule is to never use the aircraft brakes to slow the rearward roll. The aircraft will sit on its tail everytime. All of this is to illustrate how strong the aft airstair structure is on the 727 as well as how critical weight and balance limitations are on this particular aircraft. The conclusion drawn from this information is reports of landing a 727 with the airstair extended cannot be true.

A bit of formatting would go a long way toward making this more readable. Maybe that's why I'm not seeing how your reasoning supports your conclusion that one cannot(?) land a 727 with the rear stairs open. Also, just because one shouldn't doesn't mean that they didn't in this one very special case, and you don't seem to address the case of the specific, hijacked aircraft that was asked about.

Also, please note Peter Schilling's answer (posted after yours) that includes ATC transcripts indicating that they in fact did land with the rear air stairs open. The stairs did  hit the tarmac, but, it seems only once the aircraft slowed to taxi speed. It seems that your conclusion is flat wrong.

Basically his answer is correct. unless they landed flaps up  with a very flat attitude or disabled the B System hydraulics so that the the stairs were floating.

@Raffles as you admit in your answer, it's possible that the stairs didn't lock down. This is corroborated by the ATC transcript provided in Peter Schilling's answer. While I agree with both of you that landing with the air stairs locked down would cause significant damage, the facts of this incident show that they never did lock down, therefore the final conclusion in this answer that it "cannot be true" is categorically wrong since history proves that it is actually true. Also, causing damage and not being possible are 2 different things.

@FreeMan you are right about the last sentence. The author should revise it.

"Just the weight of the demountable engines" -- can you phrase this more clearly?  Most readers will have no idea of which engines are "demountable" and which are not.


text:
How can a foreign pilot get renter's insurance in the USA?
I'm about to go to the United States and do some flying. I sorted out my FAA license conversion but I was wondering how to get aircraft renter's insurance. It seems that some schools / clubs require this, and it's not included in the hire contract.
I googled a bit but it's seems that all the policies are for US residents and annual contracts. I'm more interested in a month or so.
Anybody else who's had this problem? Any suggestions ?

Are you looking to rent an aircraft from a school and fly with that for a month? If so, tell me I'm currently staying with a flight school so I might be able to get you some information.

Hi Maverick283. Thanks. I plan to hire a plane (172-ish) just for a few days (back to home airport every evening) total time probably around 5h. Nothing special really.

Do you already have renter's insurance in your own country? If so, can you get US coverage added to your existing policy? If you're going to be using the same FBO/school for a month, you could ask them to contact their insurance company as well.

Most flight schools in the US have an easy policy for renting out their planes:
You go there, you do a checkout flight on an airplane with one of their instructors, and you can go ahead and fly as much as you want.
The planes are then insured by the flight school, and you pay for the insurance by paying an hourly fee to the flight school. The checkout flight is necessary for the insurance, and is most of the time valid for 90 days. After that, another checkout flight might be required.
You, though, might not be included in that insurance. If something happens to you, the flight school's insurance will probably not cover the costs you might have.
I don't want to advertise on here, but for if you are interested I can show you a nice flight school in Florida.

I don't know about "most", but definitely enough that you should be able to find one. The devil is in the details a though: Some of these policies cover the school and the aircraft, but not the pilot. As with all insurance you should read the policy carefully before you rely on it.

Thats a good point, didnt even think about that and will add it to the answer!

If you damage an aircraft the FBO's insurance company is probably going to start by going after the pilot personally for the money and they'll only pay out themselves if they can't recover it that way. So it isn't just about "if something happens to you"; you can still be held liable even if the FBO's insurance would cover the damage. This is why it's very difficult to give any useful answers about insurance: policies are different everywhere.


text:
How do I interpret electrical system indications in a G1000 C-182?
I recently switched to a G1000 equipped aircraft C182 and trying to figure out the specifics of the G1000 and how it works in the 182.
One that I can't really figure out with the manual and the POH  is the Electrical System
I have the following Indication (in flight around 30 min after takeoff)
M        BUS      E
28.0     VOLTS    28.0

M        BATT     S
+1.5     AMPS     +0.3

Does this mean that the main and the backup battery delivery 28 Volts?
The + Amps mean that the alternator is charging the batteries ?
I noticed that the BATT Amps (M) never goes to 0 is that normal? I remember from the old analogue gauges that at some point they stay in the middle/0.
What are normal/acceptable values for BUS/BATT in a C182T?

You can find this in the C182T Operating Handbook. Section 3 has information about what values should be considered a malfunction:

HIGH VOLTS ANNUNCIATOR COMES ON OR M BAT AMPS MORE THAN 40

It also says that the M bus should be at least 20 volts in normal operation:

The Main Battery supplies electrical power to the Main and Essential
  Buses until M BUS VOLTS decreases below 20 volts. When M BUS VOLTS
  falls below 20 volts, the Standby Battery System will automatically
  supply electrical power to the Essential Bus for at least 30 minutes.

Section 4 has the expected values when starting the engine:

BUS E Volts

CHECK (Verify 24 VOLTS minimum shown)

M BUS Volts

CHECK (Verify
  1.5 VOLTS or less shown)

BATT S Amps

CHECK (Verify discharge shown (negative)

Section 7-54 describes the electrical system in detail, including wiring diagrams. It says:

Normal bus voltages with the alternator operating shall be about 28
  volts.

And:

Indicated voltages between
  24.5 and 28 volts may occur during low engine RPM conditions

As for the ammeter:

A positive current value (shown in white) indicates that the battery
  is charging. A negative current value (shown in amber) indicates that
  the battery is discharging. In the event the alternator is not
  functioning or the electrical load exceeds the output of the
  alternator, the main battery ammeter indicates the main battery
  discharge rate. In the event that Standby battery discharge is
  required, normal steady state discharge should be less than 4 amps.

So long story short, all the information you need is in the POH and the best way to get all the details is to read it carefully. Your POH may be slightly different from the one I've quoted here, so if there are any differences then you should follow it, not this answer.

This all very much depends on the specific aircraft and how its set up but in general..
+Amps means that the system is charging (pushing current onto the batteries/across the ammeter reading the current in the system). An ammeter in a system is mainly to know if you are drawing from the batteries or pushing to them in other words indicating an alternator fault. I would say anything in the + range is fine. If you really want to test it out, next time you are in the plane (and able to) try running all the lights and electronics at the same time. If your current stays in the + or 0 then your alternator is supplying enough current to run everything at once. I would not worry about +.30 Amps and frankly I would look to see what the acceptable accuracy of that meter is.
For voltage it sounds like your plane has a 24V system. Generally alternators run at a higher voltage so you can charge the battery. Again this reading is more to know of a failure. Your alternator most likely has a voltage regulator on it so you get a single (or close to it) voltage across the RMP range. Alternators will generate varying voltage across the RMP range so you need to smooth that out as you can damage or under power your electronics. If you start to see the voltage vary as you spin up the engine and slow it down you may have a bad alternator or voltage regulator.

So in summary, quick answers AFAIK to your questions on what the displays mean:
Indications (in flight around 30 min after takeoff):

M        BUS      E
28.0     VOLTS    28.0

Your Main (M) Bus voltage is 28.0 V.
Your Essential (E) Bus voltage is 28.0 V.
M        BATT     S
+1.5     AMPS     +0.3

Your Main (M) battery is slightly charging at 1.5 A.
Your Standby (S) battery is slightly charging at 0.3 A.
Yes, +Amps means the alternator is charging the battery.
Note 1): -Amps i.e. a negative value, would mean the battery is discharging, which could occur if you have various switches/equipment turned on and if for example (a) the engine is running at low/idle RPM such that the current generated from the alternator is less than the total current drawn, or (b) the alternator is not running at all such as when either the engine is stopped or the alternator drive belt has broken.
Note 2): The Main battery and Standby battery are both (nominal) 24 V batteries connected to a (nominal) 28 V system so I don't believe it is abnormal to have a slight charging current 30 minutes into a flight, but you could mention your observation to your aircraft mechanic to check whether those values are within the normal range.
Note 3): Those relatively low currents may not have caused a noticeable deflection in an old analog gauge.  For example if that gauge had a range -40 A to +40 A then 1.5 A would have been less than 2% of the full-scale deflection so it could have appeared as if the needle is sitting "in the middle" at "0" even though there is 0.3 A or 1.5 A charging current.
That's just AFAIK but if the POH or a licensed A&P mechanic tells you differently then obviously go according to the higher authority!


text:
Can someone retake a denied medical?
If someone gets a denial on their medical or gets deferred but never follows up with the appointments, can they retake it at a later time?
For example, if someone gets denied on their medical and they want to retake the exam 10 years later will the original denial prevent them from passing?

This is my personal experience having nearly lost my medical: If you are in the U.S., you will have to check the box on the application stating that your medical has been denied in the past. You will have to check that box every time you apply in the future. Having nearly had my medical denied in the past, my advice is to 1) find the most senior AME in your area and schedule an appointment for consultation. Explain your situation and take his/her advice. 2) Follow through on that advice (I had to see a well-regarded neurologist for a few hours' worth of exams and interrogation). Bring those results/reports with you to your next AME visit and have him/her send them to the FAA with your next medical application. The FAA's medical office in Oklahoma City will review your case and most likely send you a letter. I was able to get a medical issued the day I applied, however, the letter I received from OK City put me on a six month schedule before the age of 40. I strongly urge you to consult with the most senior AME you can find.
tl;dr - If you have been previously denied. You will have to provide documentation to your AME to overturn the denial.
Caveat: I am only familiar with the U.S./FAA system as a pilot.
[ I'll try to tidy this up when I get home later today ]

My experience is, if you come to a medical examinator with any condition, he will usually want to consult it with any more senior one and having multiple papers from specialists confirming the condition is not limiting much

Not necessarily.  The condition, if you still have it, that caused the denial may have been subject to policy changes that have eased the impact of the policy.  Once upon a time you were permanently grounded with high blood pressure, now, not if it is controlled with approved medications, and the cutoff is higher.  Same with Type 2 diabetes.  Same with some types of arrhythmias.
In Canada they are now allowing airline pilots to fly (yes, restricted Cat 1 medicals) with (carefully controlled and monitored, with tight restrictions) Type 1 diabetes.  I knew a manufacturer exp test pilot who was allowed to fly with Parkinsons by demonstrating competency in front of his doctor in the Sim until the tremors got too severe and he had to retire.  I know of an airline pilot who was signed off to fly with one eye.
There is way more discretion in medical issues now. Retake the exam and see what happens.


text:
Do pilots have to consider unplanned delays for Part 135 duty time exceedance?
When flying under Part 135, is it legal to takeoff knowing that you will exceed the allowable duty time due to an unplanned delay after the start of taxi?
135.267(d) says:

Each assignment under paragraph (b) of this section must provide
  for at least 10 consecutive hours of rest during the 24-hour period
  that precedes the planned completion time of the assignment.

So if the determining factor is the planned completion time of the assignment, am I good if my passengers showed up late on an earlier leg, or if I have to wait at the runway for 30 minutes before I takeoff if it will cause me to exceed the limit?

Note that if you operate under §135.267(b), that there isn't any specific duty time definition -- there are only regulations concerning the maximum flight time and minimum rest time in §135.267(d) (see this question for the definition of rest time). In a FAA Civil Penalty Order, it is noted that duty time is:

any time that is not a rest period.

If you're operating under §135.267(c), "a regularly assigned duty period" is also not defined, however, a legal interpretation in 2009 states that:

a pilot under a regularly assigned duty period "comes to work and ... goes home at the same time every day".

Now the question is, whether late passengers or being held up by ATC would be considered as affecting "the planned completion time of the assignment". The FAA has held in prior legal interpretations that:

delays caused by late passenger or cargo arrivals, maintenance
  difficulties, and adverse weather are beyond the control of the
  certificate holder.

And in another legal interpretation:

delays due to air traffic control, mechanical problems, or adverse
  weather could constitute circumstances that are beyond the control of
  the certificate holder.

However, it is noted that these provisions only apply if the original schedule was realistic. For example, if it is typical that ATC will place aircraft into a hold for 1 hour and this is not taken into account, this could be considered an "unrealistic" schedule for the purposes of §135.267.
Note that if no initial "planned completion time of the assignment" was calculated prior to accepting an assignment though, then "being late" may not be a legal defence if taken to court. In 1995, a case involving Charter Airlines, Walker and Mort questioned whether it was a violation of §135.267(b) & §135.267(d) to accept a flight even when it was known that the cargo would be late to arrive.
Because it was found that there was no "planned completion time of the assignment", they were on duty when waiting for the cargo (and therefore not "free of all obligations") and they had accepted the assignment after it was aware that the incoming cargo would be late, the FAA issued civil penalties amounting to \$10000 for Charter Airlines, and \$2000 each for Walker and Mort.

I believe that the law applies to the information provided the flight plan. Since this document is often used for lawful evidence in other areas of aviation, it would make sense for this to be what is used for "planned" flight.

Welcome! Thanks for your answer - are you able to expand on it at all? Perhaps by citing sources.


text:
Is roll control achieved exclusively with spoilers on an A320 on final approach?
As a private pilot I have zero knowledge about how big jets are being flown so I was a little surprised to see that smaller Airbuses (A32x) only use spoilers for roll control on final approach.
During the initial phase of the approach ailerons are being used but at a certain point they stay in the neutral position and roll is controlled by the spoilers.
When I mentioned this to the pilot when exiting the aircraft he was a little annoyed by the question and he said I must have seen it wrong. I've seen this numerous times since then so I'm pretty sure I wasn't mistaken.
Is this actually how the spoilers are used on approach, and if so, why?

The B738 uses spoilers primarily for roll control as well on final. Although I've seen a bit of aileron movement, most of the corrections are using spoilers. Also clueless as to why, wing-tip-stall risk perhaps? I understand swept-wing aircraft stall tip first.

Airbus has various versions of the aileron and spoiler control system on the A320 family. But all these control surfaces are used together to control roll, yaw and alleviate gust loading on the wing. On the short field kit, the ailerons will move upwards on both sides to assist in steeper descent. It is very common to use spoilers for roll control during low speeds, most big jets use it.

Spoilers and ailerons are both used on the approach -- the computers on the Airbus dictate how much control deflection is required, but I don't know the criteria for the ratio between aileron and spoiler deflection.

Every time I observed the control surfaces during final approach, the ailerons didn't move at all. The spoilers on the other hand moved constantly. Even during a very gusty approach at LHR the ailerons remained fixed in the neutral position.

You might want to take a look at this YouTube video (just found one by the first few results when searching). From what I can see, there's definitely aileron movement on final.

@DeltaLima You should add your comment as an answer to this question. Although it still wouldn't answer the question "why?"

Are you sure the ailerons stayed at the neutral position?  In the dense air at low altitudes, the ailerons have so much control authority that they only need to move a tiny amount in order to give you the roll response you want; if you look closely, you should see that the ailerons do move a bit even on final approach.

@Sean Yes I'm sure. I can see them move on takeoff every time, but they didn't move at all on landing.

Downward aileron travel must be restricted when flaps are deflected. Since flaps change the local incidence on the flapped part of the wing, the outer wing will experience an increase in its local angle of attack. The increased suction over the inner wing will accelerate not only the air flowing over the inner wing, but also that air which will flow over the outer wing as well. Left to itself, the outer wing would stall if powerful Fowler flaps are deployed on the inner wing.
Adding slats will push the stall angle of attack up, and now the outer wing is back in business. However, if the aileron is deflected downwards, the stall angle of attack is reduced again. The outer wing could stall simply due to the aileron deflection!
I do not need to point out that an asymmetric stall on approach is extremely undesirable.
Now roll control could still be achieved by only moving one aileron upwards. But this would decrease the induced drag at the wingtip at low speed. Remember, at low speed the induced drag is dominant (it is proportional to the inverse of the flight speed squared), so the drag change due to an aileron deflection will cause an inverse yawing moment at a time when the pilot wants to keep the aircraft lined up with the runway.
Using the spoilers instead will incur a higher lift loss for the same rolling moment, but will also increase local drag, which creates a helpful yawing moment into the opposite direction of the one created by upward aileron deflection. Also, the change in local lift from spoiler deflection is much greater once the flaps are fully deployed. This means that spoilers are much more effective for roll control in the landing configuration than in the take-off or cruise configurations.
THAT's why spoilers are preferred for roll control on approach. I am surprised, however, that you observed no aileron motion at all. Normally, the ailerons are still used, but with a much restricted travel range, as @DeltaLima mentions in his answer.

This HD video of an A320 landing in Chicago shows that the ailerons move all the time during the approach, although the excitations are very limited from the moment the final flaps are selected. It seems there is some kind of limiting functions activated.
Airbus has various versions of the aileron and spoiler control system on the A320 family. It is important to note that all these control surfaces are used together to control roll, yaw and alleviate gust loading on the wing. On the short field kit, the ailerons will move upwards on both sides to assist in steeper descent.
It is very common to use spoilers for augmented roll control during low speeds, most big jets use it. It is sometimes observed that spoilers deploy partially during takeoff under strong crosswind conditions. Here is an example of a B767 that has spoilers deflected during most of the take-off roll.